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SERVICE MANUAL

1. 1 Clean the filter mounting surface on the front case 2 Apply engine oil to the oil filter s O ring 3 Screw on the oil filter until the O ring is seated on the mounting sur face Then give the oil filter one further turn such that it is torqued to approximately 10 33 ft lbs 14 Nm Caution The oil filter must be tightened using a commercially available filter wrench If the filter is tightened by hand only it will be insufficiently torqued resulting in oil leaks 25 Pistons and Connecting Rods REMOVAL AND INSTALLATION Apply engine oil to all moving parts before installation Removal steps 1 Connecting rod nut 7 Piston ring No 2 2 Connecting rod cap 8 Oil ring 3 Connecting rod bearing 9 Piston pin 4 Piston and connecting rod assembly 10 Piston 5 Connecting rod bearing 11 Connecting rod 6 Piston ring No 1 12 Bolt 26 2 Cylinder No Push in with piston Piston ring End gap Pistons and Connecting Rods REMOVAL SERVICE POINTS CONNECTING ROD CAP REMOVAL 1 Mark the cylinder number on the side of the connecting rod big end to facilitate reassembly PISTON PIN REMOVAL 1 Insert the Push Rod special tool from the front arrow mark side then fit guide D 2 Mount the piston and connecting rod assembly on the Piston Pin Setting Base special tool with the piston s front mark pointing upward 3 Remove the piston pin using a press NOTE
2. Removal steps 1 Timing belt upper cover 6 Crankshaft pulley 2 Timing belt lower cover 7 Camshaft sprocket bolt 3 Timing belt 8 Camshaft sprocket 4 Tensioner spring 9 Engine support bracket 5 Timing belt tensioner 10 Timing belt rear cover Timing Belt Cracked tooth base Rounded edge Abnormal wear exposed core wire REMOVAL SERVICE POINTS TIMING BELT TENSIONER SPRING TIMING BELT TENSIONER REMOVAL 1 Using pliers grip the tensioner spring projection marked A in the diagram and remove it from the oil pump case stopper Then remove the tensioner spring Remove the timing belt tensioner If the timing belt is to be reused chalk an arrow on the belt to indicate the direction of rotation before removing it This will ensure the timing belt is fitted correctly when reused UJ NJ CAMSHAFT SPROCKET BOLT REMOVAL 1 Using the special tools shown in the illustration lock the camshaft sprocket in position 2 Loosen the camshaft sprocket bolt INSPECTION 1 TIMING BELT Check the timing belt closely Replace the belt with a new one if any of the following defects is evident 1 Hardened backing rubber the backing rubber is glossy non elastic and so hard that scratching with fingernails leaves no mark 2 Surface cracks in the backing rubber 3 Splits in the canvas and or separation of the canvas and rubber 4 Cracks at the bases of teeth 5 Cr
3. The connecting rod bolts and nuts utilize the plastic region tightening method The bolts must therefore be checked for stretching before reuse To check a bolt for stretching screw the nut down the entire length of the thread by hand Unless the nut turns smoothly all the way the bolt s threaded section is stretched and the bolt must be replaced Before fitting the nuts apply engine oil to their threads and seating surfaces Fit the nuts onto the bolts and turn them until they are finger tight After this the nuts must be tightened alternately to ensure correct fit ting of the cap Tighten the nuts to a torque of 12 54 ft lbs 17 Nm Make a paint mark on the top of each nut as shown Make paint marks on the bolts 90 to 100 clockwise from the paint marks on the nuts Turn the nuts until their paint marks are aligned with the paint marks on the bolts Caution 1 If the nuts are turned by less than 90 the cap may not be held on with sufficient strength 2 If the nuts are turned by more than 100 loosen them com pletely and carry out the tightening procedure again 32 Crankshaft and Cylinder Block REMOVAL AND INSTALLATION Apply engine oil to all moving parts before installation 8 11 ft lbs 11 Nm 1 4 37 62 ft lbs 51 Nm 6 7 8 9 Removal steps Rear oil seal Rear oil seal case Rear oil seal case gasket Bearing cap bolt Bearing cap Crankshaft bearing lower Crankshaft
4. ing belt side press the pistonand connecting rod assembly into the Cylinder from the top of the cylinder 4 Compress the piston rings tightly with a suitable ring compression tool then press the piston and connecting rod fully into the cylinder Do not strike the piston hard since the piston rings may break and the crank pin may be nicked 30 Pistons and Connecting Rods Colorcode positions Wo 1 CONNECTING ROD BEARING INSTALLATION 1 Select bearings according to the crankshaft and connecting rod identifi cation marks or color codes referring to the following table Crankshaft Connecting rod Bearing identification mark identification color identification mark Whit Yellow Non None White UJ UJ wI NI gt N gt CONNECTING ROD CAP INSTALLATION 1 Aligning the marks made during disassembly fit the bearing cap onto the connecting rod If the connecting rod is new and has no index mark ensure that the bearing locking notches are both on the same side Cylinder No Locking notch 31 Pistons and Connecting Rods 90 100 Paint mark Check that the connecting rod big end side clearance confirms with specifications Standard value 0 10 0 25 mm Limit 0 4 mm CONNECTING ROD CAP NUT INSTALLATION Caution To fit the connecting rod cap nuts with the cylinder head in place the spark plugs must be removed beforehand
5. For LP Gas Vapor withdrawal Application 40 1 5 liter Gas Engine Natural Gas LP Vapor Carburetor DESCRIPTION BASE MOUNTING FLANGE FUEL INLET NIPPLE 3 4 NPT CAPSCREW HEX HD M8 1 25 X 20MM WASHER FLAT M8 WASHER LOCK M8 NUT HEX M8 1 25 SOLENOID VALVE BUSHING RED 3 4 X 3 8 FITTING BARBED 90 DEG 3 4 NPT X 5 8 HOSE 5 8 I D X 31 LONG CLAMP HOSE 10 COVER AIR CLEANER VALVE PRESSURE NATURAL GAS VALVE PRESSURE LP VAPOR NIPPLE PIPE 3 8 NPT X 4 LONG ADAPTOR AIR CLEANER CLEANER AIR WING NUT 1 4 20 CARBURETOR GASKET CARBURETOR RD HD MACH SCREW 10 24 X 1 2 WASHER LOCK 10 WASHER FLAT 10 STUD 1 4 20 X 3 LONG 1 4 20 HEX NUT 5 16 18 HEX NUT DECAL FUEL INLET STUD 5 16 18 X 1 1 2 LONG BARB FITTING 5 16H X 1 8P HOSE CLAMP 1 4 HOSE 9 32 I D HOSE 9 32 I D BARB FITTING 90 DEG 5 16H X 1 8P MANIFOLD INTAKE HHCS M8 1 25 X 16 LONG CLAMP VINYL 1 BRACKET RADIATOR HOSE oO P PO A Nanan P P BP m m m m sch m AP AND sch AND OOD m Aa m 41 1 5 Liter Gas Engine LP Liquid Carburetor Exploded View o o Harness D GE OS Serra 3 S A AN Blower Housing Mount to 42 1 5 Liter Gas Engine LP Liquid Carburetor DESCRIPTION WASHER FLAT 10 WASHER LOCK 10 RD HD MACH SCREW 10 24 X 1 2 WING NUT 1 4 20 COVER AIR CLEANER
6. After removing the piston pin keep the piston piston pin and connecting rod together Do not allow pistons piston pins and connecting rods from different cylinders to become mixed up INSPECTION 1 PISTON RINGS 1 Check the piston ring side clearance If the clearance exceeds the specified limit replace the ring or piston or both Standard values No 1 ring 0 03 0 07 mm No 2 ring 0 02 0 06 mm 2 Insert the piston ring into the cylinder bore and push it down with a piston Ensure that the piston s crown is in contact with the ring such that the ring is at 90 to the cylinder wall Then measure the end gap with a thickness gauge If the gap is too large replace the piston ring Standard values No 1 ring 0 20 0 35 mm No 2 ring 0 35 0 50 mm Cil ring 0 20 0 50 mm Limits No 1 ring 0 8 mm No 2 ring 0 8 mm Cil ring 1 0 mm 27 Pistons and Connecting Rods Connecting rod Piston pin Piston Guide B Guide A 2 CRANKSHAFT PIN OIL CLEARANCE PLASTIC Wipe all oil off the crankshaft pin and connecting rod bearing On the pin place a plastic gauge that is cut to the same length as the bearing s width The plastic gauge must be centered on the pin in parallel with the pin s axis Gently place the connecting rod cap in position and tighten the bolts to the specified torque Remove the bolts and gently remove the connecting rod cap Measure the compressed part of the plasti
7. Crankshaft bearing upper Cylinder block MP NS 33 Crankshaft and Cylinder Block f 11 Fillet rolled section INSPECTION 1 CRANKSHAFT OIL CLEARANCE The crankshaft oil clearance can be measured easily using a plastic gauge To check the crankshaft oil clearance with a plastic gauge carry out the following procedure Wipe all oil off the crankshaft journal and the bearing s inside surface Install the crankshaft Cut the plastic gauge such that its length matches the width of the bearing then place it on the journal along the journal s axis Gently fit the crankshaft bearing cap and tighten the bolts to the spec ified torque Remove the bolts and gently remove the crankshaft bearing cap Using the scale printed on the plastic gauge bag measure the plastic gauges crushed section at its widest point Standard value 0 02 0 04 mm Limit 0 1 mm NOTE The crankshaft pins and journals are fillet rolled and must not be machined to undersize dimensions 2 CYLINDER BLOCK Visually check for cracks rust and corrosion and inspect the cylinder block using a flaw detecting agent Rectify defects where possible or replace the cylinder block Ensure that the top surface is free of gasket chips and other foreign material Check the cylinder block s top surface for distortion using a straight edge and thickness gauge Standard value 0 05 mm Limit 0 1 mm Check the cylinder walls for cracks and seizure mark
8. Exhaust 1 0 mm Measure the valve s total length If the measurement is less than specified replace the valve Standard value Intake 100 75 mm Exhaust 101 05 mm Limit Intake 100 25 mm Exhaust 100 55 mm 18 Guide I D Squareness Free height Stem O D Valve stem end Valve projection Spring seating surface Cylinder Head and Valves 3 VALVE SPRINGS 1 Measure the valve spring s free height If the measurement is less than specified replace the spring Standard value intake 46 1 mm exhaust 46 8 mm Limit exhaust 46 3 mm Measure the squareness of the spring If the measurement exceeds the specified limit replace the spring Standard value 2 or less Limit 4 4 VALVE GUIDES 1 Measure the clearance between the valve guide and valve stem If the clearance exceeds the specified limit replace either or both components Standard value intake 0 020 0 050 mm exhaust 0 050 0 085 mm Limit Intake 0 10 mm Exhaust 0 15 mm 5 VALVE SEATS 1 Assemble the valve then measure the valve stem projection between the end of the valve stem and the spring seating surface If the measurement exceeds the specified limit replace the valve seat Standard value intake 43 70 mm exhaust 43 30 mm Limit intake 44 20 mm exhaust 43 80 mm 19 Cylinder Vaive height Head and Valves 0 9 1 3 mm KNN N seat WLLL ddd Ov
9. guide hole in the cylinder head to match the over size valve guide that is to be fitted Caution Do not install a valve guide of the same size again Valve guide hole diameters 0 05 O S 12 050 12 068 mm 0 25 OS 12 250 12 268 mm 0 50 O S 12 500 12 518 mm 20 Projec tion Spring Painted retainer end Stem seal Spring seat Cylinder Head and Valves 3 Press fit the valve guide until it projects by the specified amount Standard value 17 mm Caution 1 The valve guide must be installed from the upper side of the cylinder head 2 The valve guides differ in length on the intake and exhaust sides 3 After press fitting the valve guide insert a new valve and check that it slides smoothly INSTALLATION SERVICE POINTS VALVE STEM SEAL INSTALLATION 1 Install the valve spring seat 2 Install a new valve stem seal using the special tool shown in the illus tration Caution 1 Valve stem seals cannot be reused 2 The valve stem seal must be installed using the correct spe cial tool Incorrect installation could result in oil leaking past the valve guide VALVE SPRING INSTALLATION 1 Install the valve spring such that its painted end is on the rocker arm side Paint colors Intake Orange Exhaust Yellow RETAINER LOCK INSTALLATION 21 Cylinder Head and Valves CYLINDER HEAD BOLT INSTALLATION 1 DH cU T Before reusing the cylinder head bolt che
10. pan 7 Drain plug 39 Oil screen 18 An Front case 13 E D Relief piug 44 Oil pump cover 10 Pistons and connecting rods Connecting rod nut 17 90 to 100 12 54 90 to 100 Crankshaft and cylinder block Rear oil seal case 11 Bearing cap Section 1 Ignition System REMOVAL AND INSTALLATION Removal steps Oil level gauge Oil level gauge guide O ring Spark plug cable Spark plug Distributor O ring DONUT NS 8 73 ft lbs 12 Nm y 18 44 ft lbs 25 Nm 16 97 ft lbs d Nm 2 REMOVAL SERVICE POINT CRANKSHAFT BOLT REMOVAL 1 Lock the flywheel or drive plate in position using the special tool shown in the illustration then loosen the crankshaft bolts INSTALLATION SERVICE POINTS DISTRIBUTOR INSTALLATION 1 Turn the crankshaft clockwise until cylinder No 1 is at top dead center on its compression stroke 2 Align the alignment marks on the distributor housing and coupling 3 Fit the distributor onto the engine aligning the stud bolts with the slots in the distributor mounting flange CRANKSHAFT BOLT INSTALLATION 1 Lock the flywheel or drive plate in position using the special tool shown in the illustration then tighten the crankshaft bolts Timing Belt REMOVAL AND INSTALLATION 64 91 ft lbs 8 11 ft lbs 88 Nm 25 82 ft lbs 35 Nm
11. ring spacer into the piston ring groove Then fit the upper and lower side rails NOTE 1 The spacer and side rails may be fitted in either direction No dis tinction is made between top and bottom 2 Spacer and side rail sizes are color coded as follows Size Color STD None 0 50 mm O S Blue 1 00 mm S Yellow 2 install a side rail fit one end of the rail into the groove then press the rest of the rail into position by hand as shown Caution Do not fit side rails using a piston ring expander since they may break 3 After installing the side rails check that they move smoothly in both directions 29 Pistons and Connecting Rods 1T identification mark eT identification mark Size mark Side rail No 1 ring Piston pin No 2 ring and Side rail PISTON RING No 2 PISTON RING No 1 INSTALLATION 1 Using a ring expander fit ring No 2 and ring No 1 with their identi fication marks facing upward on the piston crown side Identification marks No 1 ring 1T No 2 ring 2T NOTE Piston rings are stamped with size marks as follows Size Size mark STD 0 50 mm O S 1 00 mm S PISTON AND CONNECTING ROD ASSEMBLY INSTALLATION 1 Apply oil to the piston piston rings and oil ring 2 Align the gaps of the piston rings and oil ring side rails and spacer as shown 3 With the piston crown s front arrow mark pointing toward the tim
12. 10 1 50 X 70 LG HHCS M10 1 50 X 90 LG WASHER FLAT 5 16 M8 WASHER LOCK 5 16 M8 HEX NUT 5 16 18 HHCS M10 1 25 X 20 LG HHCS M6 1 0 X 16 LG HHCS M10 1 25 X 45 LG HEX NUT M10 1 25 HEX NUT M8 1 25 SHCS M8 1 25 X 25 LG HHCS 5 16 18 X 1 LG ADAPTER THERMOSTAT GASKET WATER OUTLET THERMOSTAT GASKET INTAKE MANIFOLD MANIFOLD INTAKE SENSOR WATER LEVEL SWITCH WATER TEMPERATURE FITTING HOSE BARB 3 8 P X 5 8 H FITTING PIPE PLUG 3 8 NPT FITTING PIPE PLUG 1 8 NPT 8 1 25 X 20 LG TUBE WATER INLET SEAL O RING LEG RIGHT ENGINE SUPPORT SPACER SWITCH OIL PRESSURE FITTING STREET ELBOW 1 8 NPT ADAPTER OIL PRESSURE SWITCH FITTING PIPE PLUG 1 4 NPT HHCS M10 1 5 X 110 LG 8 1 25 X 35 LG HHCS M12 1 25 X 55 LG WASHER LOCK M12 PULLEY CRANKSHAFT 1800 RPM PULLEY CRANKSHAFT 3600 RPM BRACKET ALTERNATOR SUPPORT DC ALTERNATOR 12V BRACKET ALTERNATOR ADJUSTMENT HHCS M6 1 0 X 70 LG WASHER FLAT 1 4 M6 FAN RADIATOR PULLEY FAN V BELT 1800 RPM V BELT 3600 RPM SPACER FAN PULLEY FILTER OIL ADAPTER OIL DRAIN CLAMP HOSE HOSE ASM OIL DRAIN CAP OIL DRAIN HOSE d Om ob 1 1 1 1 1 1 8 2 4 14 16 1 1 4 2 1 2 1 1 2 3 2 2 23 2 1 2 2 1 10 5 2 1 1 1 1 1 1 1 1 1 1 6 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 4 4 1 1 1 1 1 1 1 1 1 1 39 1 5 liter Gas Engine Natural Gas LP Vapor Carburetor Exploded View
13. GENERAC POW ER SYSTEMS INC MITSUBISHI GAS IN LITER ENGINE SERVICE MANUAL FOREWORD This manual has been published by GENERAC POWER SYSTEMS INC to aid our dealers mechanics company service personnel and general consumers when servicing the products described herein It is assumed that these personnel are familiar with the servicing procedures for these products or like or similar products manufac tured and marketed by GENERAC POWER SYSTEMS INC It is also assumed that they have been trained in the recommended servicing procedures for these products which includes the use of mechanics hand tools and any special tools that might be required Proper service and repair is important to the safe economical and reliable operation of the products described herein The trou bleshooting testing service and repair procedures recommended by GENERAC POWER SYSTEMS INC and described in this manual are effective methods of performing such operations Some of these operations or procedures may require the use of specialized equip ment Such equipment should be used when and as recommended We could not possibly know of and advise the service trade of all conceivable procedures or methods by which a service might be per formed nor of any possible hazards and or results of each proce dure or method We have not undertaken any such wide evaluation Therefore anyone who uses a procedure or method not recom mended by the ma
14. SE ANTI FREEZE AND SOFT WATER IF DESIRED A HIGH QUALITY RUST INHIBITOR MAY BE ADDED TO THE RECOMMENDED COOLANT MIXTURE WHEN ADDING COOLANT ALWAYS ADD THE REC OMMENDED 50 50 MIXTURE ENGINE OIL USE A HIGH QUALITY DETERGENT OIL CLASSIFIED FOR SERVICE SC SD SE OR SF DETERGENT OILS KEEP THE ENGINE CLEANER AND REDUCE CARBON DEPOSITS USE OIL HAVING THE FOLLOWING SAE VISCOSITY RATING BASED ON THE AMBIENT TEMPERATURE RANGE ANTICIPATED BEFORE THE NEXT OIL CHANGE TEMPERATURE RECOMMENDED OIL GRADE ABOVE 86 F 30 C 32 F TO 85 F 0 29 C BELOW 32 F 0 All Seasons SAE 40 SAE 30 SAE 20W SAE 10W 30 PERIODIC MAINTENANCE SCHEDULE A EVERY THREE MONTHS 1 Check battery state of charge and condition 2 Inspect and test fuel system 3 Check transfer switch 4 Inspect exhaust system 5 Check engine ignition system 6 Check fan belts B ONCE EVERY SIX MONTHS 1 Test engine safety devices low oil pressure low coolant level high coolant temperature C ONCE ANNUALLY 1 Test engine governor adjust or repair if needed 2 Clean and inspect generator 3 Flush cooling system D FIRST 100 OPERATING HOURS 1 Change engine oil and filter After initial change service engine oil and filter at 150 operating hours or 6 months whichever comes first 2 Retorque cylinder head 3 Retorque intake and exhaust manifold E EVERY 500 OPERATING HOURS 1 Service air cl
15. STUD 1 4 20 X 3 LONG 1 4 20 HEX NUT CLEANER AIR ADAPTOR AIR CLEANER HOSE 9 32 I D HOSE CLAMP 1 4 BARB FITTING 5 16H X 1 8P CARBURETOR GASKET CARBURETOR STUD 5 16 18 X 1 1 2 LONG CLOSE NIPPLE 3 8 NPT ELBOW BRASS ST 1 4 NPT ELBOW 3 8 NPT X 5 8 VAPORIZER LP GAS HOSE CLAMP 10 HOSE 5 8 I D SAE 20R3 32 BARBED ST 1 2 X 5 8 HOSE 5 8 I D X 18 BARB FITTING 90 DEG 5 16H X 1 8P HOSE 9 32 I D MANIFOLD INTAKE WASHER LOCK M8 5 16 18 HEX NUT FITTING BARBED 90 DEG 3 4 NPT X 5 8 HOSE 5 8 I D SAE 20R3 18 KIM HEATER 500W 1020 BRACKET HEATER HHCS M6 1 00 X 16 LONG WASHER LOCK 1 4 M6 NUT HEX M6 1 0 WASHER FLAT 1 4 M6 MOUNTING BASE BULKHEAD ADAPTOR FUEL SOLENOID LP LIQUID NIPPLE 1 4 NPT DECAL FUEL INLET WIRE FUEL SOLENOID BRACKET VAPORIZER BRACKET RADIATOR HOSE FITTING 90DEG 1 4 NPT X 7 16 COUPLING PIPE 1 4 NPT FUEL LINE LPG 24 5 LONG d JO N Sn CA CAN sch sch sch ch sch Mib P P A MAM OO h A ch sch h EI sch 5 P Ch sch ch ch ch sch P P P 43 GENERAC POWER SYSTEMS INC Manual Part No C1947
16. acks in the side of the belt 6 Abnormal wear on the belt s sides NOTE The sides of the belt are normal if they are sharp as if cut by a knife Timing Belt 7 Abnormal wear on teeth Canvas wom exposing rubber Initial stage Canvas worn fluffy canvas fibers rubbery texture gone white discol oration canvas texture indistinct Missing tooth Final stage Canvas worn exposing rubber tooth width reduced 8 Missing teeth 2 TENSIONER PULLEY AND IDLER PULLEY 1 Check that the pulleys turn smoothly without play and are not abnormally noisy Replace either or both of the pulleys if necessary INSTALLATION SERVICE POINTS CAMSHAFT SPROCKET BOLT INSTALLATION 1 Using the special tools shown in the illustration lock the camshaft sprock et in position 2 Tighten the camshaft sprocket bolt to the specified torque TIMING BELT TENSIONER TENSIONER SPRING INSTALLATION 1 Lock the timing belt tensioner in the illustrated position 2 Fit one of the tensioner spring projections over the hooked portion of the timing belt tensioner and fit the tensioner onto the oil pump case 11 Timing Belt 1 2 Grip the other tensioner spring projection and fit it onto the oil pump case lug as shown in the illustration Move the timing belt tensioner in the direction shown and temporarily tighten the bolt TIMING BELT INSTALLATION Align the camshaft timing mark with the timing mark on the cylinder
17. amshaft 31 Nm Rocker Arms and Camshaft INSPECTION 1 CAMSHAFT 1 Measure the cam heights and replace the camshaft if any height exceeds the specified limit Standard value Intake 38 78 mm 1 53 in Exhaust 39 10 mm 1 54 in Limit intake 38 28 mm 1 51 in Exhaust 38 60 mm 1 52 in 2 Reassemble the camshaft into the cylinder head The end with the dowel pin should face the front of the engine ROCKER ARM ROCKER SHAFT ASSEMBLY INSTALLATION D USA 1 Assemble the rocker arms and rocker shaft paying attention to D mm the identification marks Then mount the assembly on the cylin der head DIS UM WW CAMSHAFT OIL SEAL INSTALLATION Refer to illustration at left ROCKER COVER INSTALLATION Using a new gasket install the rocker cover onto the cylinder head Refer to the exploded view on page 10 15 Cylinder Head and Valves REMOVAL AND INSTALLATION Apply engine oil to ail moving parts before installation Removal steps Cylinder head bolt Cylinder head assembly Cylinder head gasket Retainer lock Valve spring retainer Valve spring Intake valve primary Intake valve secondary Retainer lock Valve spring retainer Valve spring SS 0909 VI SUN o Exhaust valve Valve stem seal Valve spring seat Valve stem seal Valve spring seat Intake valve guide Exhaust valve guide Intake valve seat primary Intake valve seat secondary Exhaust valve seat Cylin
18. c gauge at its widest point using the scale printed on the plastic gauge bag Standard value 0 02 0 04 mm Limit 0 1 mm INSTALLATION SERVICE POINTS PISTON PIN INSTALLATION 1 Q 3 4 5 6 7 Measure the following lengths as shown A Piston boss to piston boss outside dimension B Piston boss to piston boss inside dimension C Piston pin length D Connecting rod small end eye thickness Enter the measured values into the following formula LS A 8 D 2 Insert the Push Rod special tool into the piston pin then fit Guide A special tool Fit the piston and connecting rod together such that their front marks are on the same side Apply engine oil to the outside of the piston pin Into the front mark side of the piston insert the Guide A piston pin and Push Rod starting with guide A Screw guide B into guide A Leave a gap between the two guides of 3 mm plus the value L calculated in step 2 28 Pistons and Connecting Rods 8 Mount the piston and connecting rod on the Piston Pin Setting Base Push Rod special tool with the piston s front mark pointing upward 9 Install the piston pin using a press If the press fitting load is out of specification replace the piston pin and piston assembly or the con necting rod or both Standard value 4 900 14 700 N 1101 to 3303 pounds 2777277772 le N NE SE N NF Side rail OIL RING INSTALLATION 1 Fit the oil
19. ck that its nominal length does not exceed the specified limit Replace the bolt if this measure ment exceeds the limit Limit 103 2 mm Fit the washer as shown Apply engine oil to the bolt s thread and washer Tighten the bolts in the sequence shown until each is torqued to 36 14 ft lbs 49 Nm Completely loosen the bolts Retighten the bolts in the sequence shown until each is torqued to 14 75 ft lbs 20 Nm Apply paint marks to the cylinder head bolt heads and cylinder head as shown In accordance with the tightening sequence tighten each bolt by 90 Tighten each bolt by a further 90 and check that the paint marks on the bolt head and cylinder head are aligned Caution If the bolts are tightened by an angle of less than 90 they may not hold the cylinder head with sufficient strength If the bolts are tightened by an angle exceeding 90 complete ly remove them and carry out the installation procedure again 22 REMOVAL AND INSTALLATION gt Apply engine oil to all moving parts before installation Removal steps Oil filter Oil pan Oil screen Gasket Relief valve Relief valve spring Relief plunger Se ew ee 32 45 ft lbs 44 Nm 23 10 11 12 13 Oil Pump and Oil Pan 5 16 ft lbs 7 Nm Front oil seal Front case O ring Oil pump cover Oil pump outer rotor Oil pump inner rotor Oil Pump and Oil Pan REMOVAL SERVICE POINTS OIL PAN REMOVAL 1 Remov
20. der head Cylinder Head and Valves REMOVAL SERVICE POINTS CYLINDER HEAD BOLT REMOVAL Refer to illustration at left RETAINER LOCK REMOVAL 1 Tag removed valves springs and other components noting their cylinder numbers and locations to facilitate reassembly Store these components safely VALVE STEM REMOVAL Refer to illustration at left 17 Cylinder Head and Valves Contact must be in center of face INSPECTION 1 CYLINDER HEAD 1 Before cleaning the cylinder head check it for water leaks gas leaks cracks and other damage Remove all oil water scale sealant and carbon After cleaning the oil passages blow air through them to verify that they are not blocked Check for distortion in the cylinder head gasket surface using a straight edge and thickness gauge If distortion exceeds the specified limit grind the gasket surface to specification Gasket surface distortion Standard value 0 05 mm or less Limit 0 2 mm Grinding limit 0 2 mm Cylinder head height specification when new SOHC 106 9 107 1 mm Caution No more than 0 2 mm of stock may be removed from the cylin der head and cylinder block mating surfaces in total 2 VALVES 1 2 Check the valve face for correct contact If contact is uneven or incomplete reface the valve seat If the margin is less than specified replace the valve Standard value Intake 1 0 mm Exhaust 1 5 mm Limit Intake 0 5 mm
21. e the oil pan mounting bolts 2 Knock the special tool between the oil pan and cylinder block as shown in the illustration 3 Tapping the side of the special tool slide the tool along the oil pan cylinder block seal and thus remove the oil pan INSPECTION 1 OIL PUMP 1 Fit the rotor into the front case 2 Check the tip clearance using a thickness gauge Standard value 0 06 0 18 mm 3 Check the side clearance using a straight edge and thickness gauge Standard value 0 04 0 10 mm 4 Check the body clearance using a thickness gauge Standard value 0 04 0 10 mm Limit 0 35 mm 24 Oil Pump and Oil Pan INSTALLATION SERVICE POINTS FRONT OIL SEAL CASE INSTALLATION 1 Clean the sealant application surfaces on the cylinder block and front oil seal case 2 Apply a 3 mm bead of form in place gasket to the entire circumference of the oil pan flange FRONT OIL SEAL INSTALLATION 1 Place the special toolon the crankshaft s front end and apply engine oil to the its outer circumference N SS A ie A lon on EM guideby hand until it touches the front case Tap the oil sealinto place ES using the special tool 2 Apply engine oilto the oil seal lip then push the oil seal along the OIL PAN INSTALLATION 1 Clean the mating surfaces of the cylinder block and oil pan 2 Apply a 4 mm bead of form in place gasket to the outer circumference of the oil pan flange OIL FILTER INSTALLATION
22. eaner 2 Check starter 3 Check engine DC alternator E EVERY 800 OPERATING HOURS 1 Retorque cylinder head 2 Retorque intake and exhaust manifold 3 Check engine compression 4 Check valve clearance 1 5 Liter Gas Engine General Information Description 4G15 CARBURETOR in line OHV SOHC Combustion chamber Semi spherical type Total displacement cm 1 468 Cylinder bore mm inches 75 5 2 97 in Type Number of cylinders Piston stroke mm inches 82 0 3 23 in Compression ratio 9 0 8 Number of i Intake valve Exhaust 4 Valve timing Intake opening BTDC 14 intake closing ABDC 48 Exhaust BBDC 55 opening Exhaust closing Lubrication system Oil pump type Cooling system Water pump type ATDC 13 Pressure feed full flow filtration Trochoid type Water cooled forced circulation Centrifugal impeller type 1 5 Liter Gas Engine Specifications Rocker arms rocker shafts and camshaft Intake primary 38 78 38 28 Intake secondary 38 78 38 28 Camshaft cam height mm Camshaft journal diameter mm 45 93 45 94 ee Cylinder head and vaives 0 05 or less Flatness of cylinder head gasket surface mm Cylinder head gasket surface grinding limit including grinding of Cylinder block gasket surface mm Cyl
23. ersize hole I D VALVE SEAT CORRECTION SERVICE POINTS Before correcting the valve seat check the clearance between the valve guide and valve If necessary replace the valve guide Using the appropriate special tool or seat grinder correct the valve seat to achieve the specified seat width and angle After correcting the valve seat lap the valve and valve seat using lap ping compound Then check the valve stem projection refer to 5 VALVE SEAT in INSPECTION on page 19 VALVE SEAT REPLACEMENT SERVICE POINTS Cut the valve seat to be replaced from the inside to reduce the wall thickness Then remove the valve seat Rebore the valve seat hole in the cylinder head to match the selected oversize valve seat diameter Intake valve seat hole diameters 0 3 O S primary 27 300 27 325 mm secondary 32 300 32 325 mm Intake valve seat hole diameters 0 6 O S primary 27 600 27 625 mm secondary 32 600 32 625 mm Exhaust valve seat hole diameters 0 3 O S 35 300 35 325 mm Exhaust valve seat hole diameters 0 6 O S 35 600 35 625 mm Prevent galling of the cylinder head bore by cooling the valve seat with liquid nitrogen before press fitting it Correct the valve seat to achieve the specified width and angle refer to VALVE SEAT CORRECTION SERVICE POINTS VALVE GUIDE REPLACEMENT SERVICE POINTS 1 2 Using a press push the valve guide out toward the cylinder block side Rebore the valve
24. head Align the crankshaft timing mark with the timing mark on the front case Keeping the tension side of the timing belt tight fit the timing belt onto the crankshaft sprocket camshaft sprocket and tensioner pulley in that order Loosen the tensioner pulley mounting bolts by 1 4 to 1 2 of a turn and allow the tensioner spring to apply tension to the timing belt Turn the crankshaft twice in the normal rotating direction clockwise and check that the timing marks are correctly aligned Caution This procedure utilizes the camshaft s driving torque to apply ten sion evenly to the timing belt Be sure to turn the crankshaft as described above Do not turn the crankshaft in reverse Tighten the tensioner pulley mounting bolts Water Pump REMOVAL AND INSTALLATION Water pump 9 59 ft lbs 13 Nm INSTALLATION SERVICE POINTS WATER PUMP INSTALLATION 1 Apply a 3 mm bead of form in place gasket FIPG to the mounting surface Rocker Arms and Camshaft REMOVAL AND INSTALLATION Apply engine oil to all 3 moving parts before installation Removal steps Cil filler cap Rocker cover Rocker cover gasket Camshaft oil seal Rocker arm and shaft assembly Rocker arm and shaft assembly Rocker arm A Rocker arm spring Rocker arm B QOO M OY Ut 2 2 95 ft lbs 4Nm 22 86 ft lbs Rocker arm shaft Rocker arm C Wave washer Spacer Rocker arm D Rocker arm shaft Adjusting screw Nut C
25. inder head bolt nominal ength mm Valve margin mm intake 1 0 Exhaust 1 5 Valve stem diameter mm 6 6 Valve stem to guide Intake LU Exhaust 0 050 0 085 Valve face angle 45 45 5 Valve stem projec Intake 43 70 UDINE Exhaust 43 30 43 80 Intake 100 75 100 25 Overall valve length mm EE Valve spring free height mm Exhaust 1 5 Liter Gas Engine Specifications Valve spring load 226 40 0 Valve seat contact width mm oO Co e Valve guide internal diameter mm Valve guide projection mm NEN a 7 0 Oil pump and oil pan Oil pump tip clearance mm 0 06 0 18 Oil pump side clearance mm 0 04 0 10 Oil pump body clearance mm 0 10 0 18 Pistons and connecting rods Piston outside diameter mm 14615 755 Piston ring side clearance mm No 1 ring 0 02 0 06 i No 2 ring 0 02 0 06 Piston ring end gap clearance No 1 ring 0 20 0 35 No 2 ring 0 35 0 50 Oil ring 0 20 0 50 Piston pin O D mm 18 0 Piston pin press in load at room temperature N 4 900 14 700 Crankshaft pin oil clearance mm 0 02 0 04 Connecting rod big end side clearance mm 0 10 0 25 Crankshaft and cylinder block Crankshaft end play mm 0 05 0 18 0 25 0 1 u Oo e gt Cylinder block gasket surface grinding limit including grinding of 0 2 cylinder head gasket surface mm Cy
26. linder block overall height mm Cylinder block cylindricity mm Cylinder block I D mm Piston to cylinder clearance mm 0 02 0 04 4 REWORK DIMENSIONS Item 1 5 Liter Gas Engine Specifica Standard Cylinder head and valves Cylinder head oversize valve guide hole diameter mm Oversize valve seat ring hole diameter mm Intake primary intake secondary Exhaust 12 050 12 068 12 250 12 268 12 500 12 518 0 3 O S 27 300 27 325 0 6 O S 27 600 27 625 0 3 O S 32 300 32 325 0 3 O S 35 300 35 325 0 60 8 35 600 35 625 tions Limit 1 5 Liter Gas Engine Torque Specifications Crankshaft bolt Spark plug Oil level gauge guide 3 N 2 25 Distributor aa 1 m 23 Engine support bracket left 35 35 Idler pulley Camshaft sprocket bolt 88 Timing belt Timing belt cover Timing belt tensioner 11 1 Water pump 6 13 si Liter Gas Engine Torque Specifications Specifications Rocker arms rocker shafts and camshaft Rocker cover 4 Rocker shaft assembly Ia Adjusting screw 15 Bearing cap 24 o 11 Cylinder head and valves Cylinder head bolt 20 90 90 14 75 90 90 Tighten to 36 14 ft lbs 49 Nm then completely loosen and retighten as described Oil pump and oil pan Oil
27. ndicating front Cap No a d T a eS 4 Oil seal case Crankshaft and Cylinder Block 4 Except for the center bearing all the upper bearings are grooved The center bearings are grooveless and have flanges The center bearings are the same at the top and bottom 5 The lower bearings all grooveless BEARING CAP INSTALLATION 1 On the bottom surface of each bearing cap is the cap s number and an arrow Starting at the timing belt side fit the bearing caps in numerical order Ensure that the arrows point toward the timing belt side 2 After fitting the bearing caps measure the end play in the crankshaft If the measurement exceeds the specified limit replace the crankshaft bearings Standard value 0 05 0 18 mm Limit 0 25 mm REAR OIL SEAL INSTALLATION 1 Press fit the rear oil seal using the special tool shown in the illustration 37 1 5 Liter Gas Engine Common Parts Exploded View WATERPUMP ua HARDWARE 1 5 Liter Gas Engine Common Parts m DESCRIPTION ENGINE 1 5L CLAMP HOSE 28 PIPE FLEX EXHAUST GASKET EXHAUST MANIFOLD MANIFOLD EXHAUST SHIELD HEAT WASHER LOCK 1 4 HHCS 1 4 20 X 1 2 LG HHCS M10 1 25 X 25 LG WASHER LOCK M10 WASHER FLAT M10 LEG LEFT ENGINE SUPPORT SPACER HEX NUT M10 1 50 SHCS 5 16 18 X 3 LG STARTER 12V SPACER ENGINE PLATE HHCS M10 1 50 X 60 LG ENGINE PLATE DOWEL SLEEVE BLOWER HOUSING HHCS M
28. nes 8 kisepelglzs 9 12 SECTION 3 WATER PUMP dec 13 SECTION 4 ROCKER ARMS AND CAMSHAFT Museer rer rer 14 15 SECTION 5 CYLINDER HEAD AND VALVES cessere nnne nnne nh seeaeesenessneeseeessnenaneaeae 16 22 SECTION 6 OIL PUMP AND OIL PAN 23 25 SECTION 7 PISTONS AND CONNECTING RODS essen ener nnne snnt natn nnne 26 32 SECTION 8 CRANKSHAFT AND CYLINDER BLOCK ressentir nnne 33 37 EXPLODED VIEWS ENGINE COMMON 38 39 NATURAL GAS LP VAPOR CARBURETOR _ 40 41 LP LIQUID CARBURETOR Y 42 43 The 1 5 Liter Gas Engine has been engineered for use in Generac Power Systems products The con tents of this manual have been excerpted from the original manufacturer s service and repair manual The exploded view section at the back of this manual is for reference only For a complete listing of all engine parts refer to Generac P N PB15000G Parts Manual 1 5 Liter Gas Engine Notes 1 5 Liter Gas Engine Service Recommendations SPECIFICATIONS CRANKCASE OIL CAPACITY COOLING SYSTEM CAPACITY 4 U S QUARTS 3 79 LITERS 2 U S GALLONS 7 57 LITERS RECOMMENDED FLUIDS COOLANT USE A 50 50 MIXTURE OF LOW SILICATE ETHYLENE GLYCOL BA
29. nufacturer must first satisfy himself that neither his safety nor the product s safety will be endangered by the serv ice or operating procedure selected All information illustrations and specifications contained in this manual are based on the latest product information available at the time of publication However GENERAC POWER SYSTEMS INC reserves the right to change alter or otherwise improve the product at any time without prior notice Some components or assemblies of the product described in this manual may not be considered repairable Disassembly repair and reassembly of such components may not be included in this manual The engines described herein may be used to power a wide variety of products Service and repair instructions relating to any such products are not covered in this manual For information pertaining to use of these engines with other products refer to any owner s or service manuals pertaining to said products 1 5 Liter Gas Engine Table of Contents SERVICE 1 GENERAL INFORMATION 2 kidzelseelmE e S 3 5 TORQUE SPECIFICATIONS geeiert Deeg deeg eege deg 6 7 SECTION 1 IGNITION SYSTEM cccssessseesseeeseeeseeseeeeeeeeseeaeeeseeseaessanesseeeseesaeeeseeasseaseeesesaeseeseeeensnesseenseeeea
30. s If defects are evident bore all the cylinders to oversize or replace the cylinder block 34 Piston O D Thrust direction Crankshaft and Cylinder Block Using a cylinder gauge measure each cylinder s bore and cylindricity If any cylinder is severely worn bore all the cylinders to oversize and replace the piston and piston rings accordingly Take measurements at the points shown Standard value Cylinder bore 75 5 mm Cylindricity 0 01 mm or less 3 BORING CYLINDERS 1 Oversize pistons to be used should be determined on the basis of the Cylinder with the largest bore Oversize pistons are available with the following oversize dimensions 0 25 mm 0 50 mm 0 75 mm and 1 00 mm Measure the diameter of the piston to be used Boring must be carried out such that the piston to cylinder clearance complies with the standard value The piston s diameter should be measured at the points shown Calculate the boring finish dimension based on the piston diameter dimension e Boring finish dimension piston O D piston to cylinder clearance 0 02 0 04 mm honing margin 0 02 mm Bore each cylinder to the calculated boring finish dimension Caution To prevent distortion caused by heat increases during boring bore the cylinders in the following order No 2 No 4 No 1 No 3 Hone the cylinders to the final finish dimension piston O D piston to cylinder clearance Check the clearance be
31. tween the pistons and cylinders Standard value 0 02 0 04 mm 35 Crankshaft and Cylinder Block Color code pontoh CRANKSHAFT BEARING INSTALLATION 1 Select bearings according to the crankshaft identification marks or color codes referring to the following table If they are not identifiable measure the crankshaft journals and choose bearings to match the measurements type 1 3 Crankshaft journal Cylinder Bearing block bearing bore di ameter Identifica Journal Identifica Identifica tion mark diameter tion mark tion mark mm NO NO NO WIN Cylinder block journal bore diameter 2 Identification marks showing the cylinder block bearing bore diameter are stamped in the position shown with No 1 at the front of the engine Bearings must be selected and installed in accordance with these identifica tion marks 3 Based on the identification markings verified in steps 1 and 2 select bearings from table above See the following example 1 If the measured crankshaft journal diameter is 48 000 mm this corre sponds to classification 1 in the above table 2 If the identification mark on the cylinder block bearing hole is 1 select a bearing with an identification mark of 2 36 Grooved Upper ae Nos Lower bearing Nos 1 2 4 and 5 1 2 4 and 5 Grooveless e Upper and lower of engine Arrow i

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